1. Field of the Invention
This invention relates to a system and method for automatically identifying and dialing complete and correct codes for accessing networks, such as telephone numbers.
2. Description of the Related Art
Telephones are everywhere. Walk through a modem workplace and the musically welling tintinnabulation you hear will almost surely not be foretelling a world of merriment, as in Edgar Allan Poe's poem, but rather will be proclaiming a world of telephones.
Not long ago, technological optimists prophesied that modern telecommunications equipment such as cellular phones, fax machines and modems would help modern workers accomplish much more much faster, opening the way for shorter work weeks with undiminished productivity. What has happened, of course, is best summarized by the famous Parkinson Principle, which states that work expands to fill the time allotted for its completion. Experience has now borne out a corollary: The need for telephone numbers expands to use up all the available digits.
As numbers proliferate, so do dialing errors, and despite the best efforts of telephone designers, dialing errors continue to be a problem. One might misdial a number for any of several reasons, such as a memory lapse, accidentally pushing a button adjacent to the correct one, or not knowing or remembering the correct sequence of prefixes before the actual number. Misdialings are particularly irksome for the cell phone user on the move (who should in any event spend more time watching traffic and less time dialing numbers) and for those who make many calls in the course of a day.
Making things worse, out-of-zone phone numbers are becoming longer, even those within the same area code. In some areas, for example, the 425 area code region east of Seattle, one must now know whether the number one wants to call requires only the seven-digit subscriber number such as 123-4567, the subscriber number plus area code, that is, 425-123-4567, or the subscriber number, the area code, and a prefixed "1", that is, 1-425-123-4567. Failure to guess correctly gets one an error message saying that it is necessary to dial (or not dial) the area code and/or the prefixed "1" along with the number. Irritatingly, there are separate error messages for wrongly including (or excluding) the area code and the "1". As such, if one is dialing an unfamiliar number even within one's own area code but doesn't happen to know what prefixes are needed relative to one's own exchange, then it is possible--indeed, probable--that one will get at least one error message and requirement to re-dial.
As the need for telephone numbers increases, more and more area codes are being sub-divided. Once again, the Puget Sound area serves as an example. In 1997, the previous 206 area code became, like Caesar's Gaul, divided into three parts: 206, 425 and 253. When dialing to several cities (exchanges) near the new area code boundaries, it is often a matter of chance whether one will dial the correct area code. As is pointed out above, though, even guessing the correct area code may not be enough for success, since one must also correctly guess whether a "1" prefix is required or not.
This problem also creeps up when dialing international calls. The structure of such a number is, in most cases: (INTL ACCESS CODE)+(COUNTRY CODE)+(DOMESTIC EXCHANGE)+(SUBSCRIBER NUMBER). What many callers do not realize is that one must usually (but not always) delete some prefixed digit (typically, but not always, "0") from the beginning of the listed DOMESTIC EXCHANGE in order for the call to go through. Dialing an incorrect country code or failing to delete the prefixed digit thus creates problems identical to those encountered when one doesn't know the proper area code or whether the prefixed "1" is necessary. (Note that the "1" is the prefixed digit used in the USA instead of the internationally more common "0".) What is needed is a telephone that would either "know" or, preferably, "learn" what dialing patterns are errors and automatically correct these before submitting the number to the exchange.
It is especially easy to misdial a number when dialing quickly or when distracted. Most such errors are in only one digit, or at most two. It should not be necessary to have to redial to correct "obvious" errors in frequently dialed numbers. One's telephone or other dialing system (such as a computer-based dialing program) should be able to recognize and correct such errors. Note that failure to include or exclude one or more prefixes is a special case of a misdialed number.
Many phones have dedicated "speed-dial" buttons for frequently called numbers. Others use existing keys in combination (such as *1 through *9) to cause the phone to recall stored abbreviations for longer numbers. Some phones have both capabilities. One problem with this approach is that the number of possible buttons or abbreviations is usually small. Allowing for a large number of abbreviations, however, would create a different problem--one must then remember or have labels for all of the abbreviations. The problem is worst for cell phones, which don't allow more than about ten pre-stored abbreviated numbers, don't have room for many labels, and require the user to look away from the road to do any dialing at all. What is needed is a phone that actually reduces the time required to dial numbers and that recognizes a large number of "quick-dial" numbers without the need for dedicated keys.
In an attempt to address some of these problems, some systems have been proposed in which the phone system recognizes network-generated voice error messages such as the maddening: "We're sorry, you must first dial a `1` before dialing this number." Systems such as these suffer from several drawbacks, however: They rely on speech recognition, which won't work in all cases, in particular, if the error message is in a foreign language or changes; they may not be able to distinguish what type of error is indicated; and they do nothing to solve the other problems mentioned above, such as recognizing non-system errors such as a misdialed digit in a frequently dialed phone number.
At the heart of these shortcomings is the reliance on the "intelligence" of the system being in the remote exchange--the network exchange senses that a number has been misdialed, and issues an error message, but it usually does nothing to help the user. When it comes to sub-divided area codes, the system may put through a call dialed with the "old" area code for a time, thus performing simple error correction, but this service usually ceases after at most a few months. Of course, such "remotely intelligent" systems take no account of the dialing patterns of any particular subscriber; rather, they slavishly put through a call for even incorrectly dialed numbers as long as they sense the correct prefixes and any valid telephone number within the dialed area.